1. Field of the Invention
This invention relates to a structure for mounting an electromagnetic sound generator which generates sound by vibrating a vibration plate using an electromagnet.
2. Description of the Related Art
In the prior art, surface-mounted electromagnetic sound generators of the kinds shown in FIGS. 10 to 13 and FIGS. 14 to 17 are the thinnest and smallest available and are capable of high-density mounting. As shown in the diagrams mentioned, an electromagnetic sound generator of this type includes a case 2 in which are housed an electromagnet 10 comprising a yoke 4, a magnet 6 and a coil 8, and a vibrating plate 14 supported facing the electromagnet 10 by a ring-shaped vibration-plate supporting ring 12. The case 2 is insert-molded to have a pair of electrodes 20, 22 for connecting the coil 8, which is contained within the case 2, to substrate electrodes 18 on a substrate 16, and a dummy electrode 24 for providing greater fixing force.
The electromagnetic sound generators having the structure described above are mounted on the substrate 16 by fixing connecting portions 20a, 22a, 24a, 24b of the electrodes 20, 22 and dummy electrode 24 exposed at the exterior of the case 2 to respective ones of the substrate electrodes 18 on the substrate 16 by solder 26, as illustrated in FIGS. 11, 12 and FIGS. 15, 16.
In the conventional electromagnetic sound generators described above, the connecting portions 20a, 22a, 24a, 24b of the electrodes 20, 22 and dummy electrode 24 are formed by causing these electrodes to protrude from the bottom of the case 2 or by bending the electrodes toward the side face of the case 2. The electromagnetic sound generator is mounted on the substrate 16 with the connecting portions 20a, 22a, 24a, 24b being superimposed on the substrate electrodes 18. In order to deal with a further reduction in device thickness and size and an increase in mounting density, therefore, it is necessary that the electromagnetic sound generator itself be reduced in thickness and size. In particular, since the thickness of the electromagnetic sound generator is decided by the internal structure and mounting method of the sound generator, it is necessary to modify the internal structure and change the mounting method. However, the state of the art is such that achieving a further decrease in thickness is extremely difficult.